1. Field of Invention
This invention relates to novel dentures and to a method of preparing the same. It is particularly directed to novel dentures in which the teeth are anchored in a gum member comprising a tooth-holding portion and a mouth-engaging portion, the tooth-holding portion of which is composed essentially of non-hydrophilic polyurethane elastomer having a harness of not less than about Shore D 40 and the mouth-engaging portion of which is composed essentially of soft non-hydrophilic polyurethane elastomer having a hardness of not greater than about Shore A 65 integrally chemically bonded together into a unitary mass.
2. Prior Art
It has been proposed to provide dentures with a soft layer in contact with the gums and other mouth parts to provide tissue relief. Such soft layers have been composed of acrylics, silicones, and like rubber-like materials. But on aging, such soft layers tend to harden and give off undesirable odors. In addition, some decomposition of the polymer may also occur presumably due to an oxidation process as well as to pH fluctuations within the mouth.